275/55R18 Tire Size in Inches and Millimeters

275/55R18 tires have a diameter of 29.9" (759 mm), a tread width of 10.8" (275 mm), and a wheel diameter of 18" (457.2 mm).The sidewall of the tire is 5.9" (151 mm), and the tire's circumference is 93.9" (2383.3 mm). This means a 275/55R18 tire will make make 675 revolutions per mile, or 420 revolutions per kilometer.

275/55R18 Tire Front
275/55R18 Tire Side
Tire Circumference
675 Revs/Mile
Diameter29.9"759 mm
Width10.8"275 mm
Wheel18"457.2 mm
Sidewall5.9"151 mm
Circum93.9"2383.3 mm
Revolutions675 per mile420 per km

What Does 275/55R18 Mean?

The tire size 275/55R18 is a common size used on many trucks, SUVs, and other larger vehicles.

Here is what each part of the size designation represents:

  • 275: This number represents the width of the tire in millimeters. In this case, the tire is 275 millimeters wide.
  • 55: This number represents the aspect ratio of the tire, which is the height of the tire's sidewall as a percentage of its width. In this case, the sidewall height is 55% of the tire's width.
  • R: This letter indicates the tire's construction type. “R” stands for radial construction, which is the most common type of tire construction today.
  • 18: This number represents the diameter of the wheel that the tire is designed to fit on, in inches. In this case, the tire is designed to fit on a 18-inch wheel.

275/55R18 tire size meaning

How To Convert 275/55R18 Into Inches

The 275/55R18 conversion is fairly simple. The first number in the tire size, 275, represents the width of the tire in millimeters. To convert this to inches, we divide 275 by 25.4 (since there are 25.4 millimeters in an inch). This gives us approximately 10.8 inches.

The second number in the tire size, 55, represents the aspect ratio or the height of the tire as a percentage of its width. To calculate the height in inches, we multiply 10.8 by 0.55, which gives us approximately 5.9 inches.

Finally, the last number in the tire size, 18, represents the diameter of the wheel rim in inches. Therefore, the tire size 275/55R18 can be expressed in inches as roughly 10.8 inches wide, 5.9 inches tall, and designed to fit a 18-inch wheel rim.

Frequently Asked Questions About 275/55R18 Tires

How tall is a 275/55R18 tire?

A 275/55R18 tire has an approximate height, also known as the overall diameter, of 29.9 inches (759 mm). This height can vary slightly depending on the brand and model of the tire, as well as the amount of air pressure in the tire.

How wide is a 275/55R18 tire?

A 275/55R18 tire has a width of approximately 10.8 inches (275 millimeters). The width of the tire is the first number in the tire size designation, which in this case is “275”. It’s important to note that the actual width of the tire may vary slightly depending on the brand and model of the tire, and the width may also be affected by the amount of air pressure in the tire.

Alternate 275/55R18 Replacement Tire Sizes

Upsizing your wheels or tires? Replacement tires must be within 3% of the diametor of the original tire. The following sizes fall within that range - click on any size to see detailed info about that tire and wheel combination.

145/80R2029.1"740 mm20 mm
155/90R1829"737 mm18 mm
165/90R1829.7"755 mm18 mm
165/90R1930.7"781 mm19 mm
175/80R1829"737 mm18 mm
175/80R1930"763 mm19 mm
175/90R1729.4"748 mm17 mm
175/90R1830.4"773 mm18 mm
205/90R1529.6"751 mm15 mm
215/80R1629.5"750 mm16 mm
215/85R1529.4"747 mm15 mm
215/85R1630.4"772 mm16 mm
225/65R1829.5"749 mm18 mm
225/70R1729.4"748 mm17 mm
225/75R1629.3"744 mm16 mm
225/75R1730.3"770 mm17 mm
225/80R1529.2"741 mm15 mm
235/45R2129.3"745 mm21 mm
235/50R2029.3"744 mm20 mm
235/55R1929.2"741 mm19 mm
235/55R2030.2"766 mm20 mm
235/60R1829.1"739 mm18 mm
235/60R1930.1"765 mm19 mm
235/65R1729.1"738 mm17 mm
235/65R1830"763 mm18 mm
235/70R1730"762 mm17 mm
235/75R1629.8"758 mm16 mm
235/80R1529.8"757 mm15 mm
245/30R2429.8"758 mm24 mm
245/45R2129.6"753 mm21 mm
245/50R2029.7"754 mm20 mm
245/55R1929.6"753 mm19 mm
245/60R1829.6"751 mm18 mm
245/65R1729.5"750 mm17 mm
245/65R1830.5"775 mm18 mm
245/70R1629.5"750 mm16 mm
245/70R1730.6"776 mm17 mm
245/75R1529.5"749 mm15 mm
245/75R1630.5"774 mm16 mm
247/70R1629.6"752 mm16 mm
255/25R2429.1"738 mm24 mm
255/30R2430.1"764 mm24 mm
255/35R2229"737 mm22 mm
255/40R2129"737 mm21 mm
255/40R2230"763 mm22 mm
255/45R2029.1"738 mm20 mm
255/45R2130"763 mm21 mm
255/50R1929.1"739 mm19 mm
255/50R2030.1"764 mm20 mm
255/55R1829"737 mm18 mm
255/55R1930"763 mm19 mm
255/60R1729.1"738 mm17 mm
255/60R1830"763 mm18 mm
255/65R1629.1"738 mm16 mm
255/65R1730.1"764 mm17 mm
255/70R1529.1"739 mm15 mm
255/70R1630.1"764 mm16 mm
255/75R1530"763 mm15 mm
265/25R2429.2"742 mm24 mm
265/35R2229.3"745 mm22 mm
265/40R2129.3"745 mm21 mm
265/40R2230.4"771 mm22 mm
265/45R2029.4"746 mm20 mm
265/45R2130.4"771 mm21 mm
265/50R1929.5"749 mm19 mm
265/50R2030.5"774 mm20 mm
265/55R1829.5"749 mm18 mm
265/55R1930.5"775 mm19 mm
265/60R1729.5"750 mm17 mm
265/60R1830.5"775 mm18 mm
265/65R1629.5"750 mm16 mm
265/65R1730.6"776 mm17 mm
265/70R1529.6"753 mm15 mm
265/70R1630.6"778 mm16 mm
265/75R1530.7"779 mm15 mm
275/25R2429.4"748 mm24 mm
275/30R2430.6"776 mm24 mm
275/35R2229.6"751 mm22 mm
275/40R2129.6"753 mm21 mm
275/40R2230.7"779 mm22 mm
275/45R2029.8"756 mm20 mm
275/45R2130.7"781 mm21 mm
275/50R1929.9"759 mm19 mm
275/55R1829.9"759 mm18 mm
275/60R1730"762 mm17 mm
275/65R1630.1"764 mm16 mm
275/70R1530.2"767 mm15 mm
285/35R2229.9"759 mm22 mm
285/40R2130"761 mm21 mm
285/45R1929.1"739 mm19 mm
285/45R2030.1"764 mm20 mm
285/50R1829.3"743 mm18 mm
285/55R1830.4"771 mm18 mm
285/60R1629.4"748 mm16 mm
285/60R1730.5"774 mm17 mm
285/65R1630.6"776 mm16 mm
285/70R1530.7"781 mm15 mm
295/23R2429.4"746 mm24 mm
295/30R2229"737 mm22 mm
295/30R2330"762 mm23 mm
295/35R2129.1"739 mm21 mm
295/35R2230.1"765 mm22 mm
295/40R2029.3"744 mm20 mm
295/40R2130.3"769 mm21 mm
295/45R1929.5"749 mm19 mm
295/45R2030.5"774 mm20 mm
295/65R1530.1"765 mm15 mm
305/30R2229.3"743 mm22 mm
305/35R2129.4"747 mm21 mm
305/35R2230.4"773 mm22 mm
305/40R2029.6"752 mm20 mm
315/25R2329.2"742 mm23 mm
315/30R2229.5"749 mm22 mm
315/35R2129.6"753 mm21 mm
315/35R2230.7"779 mm22 mm
315/55R1629.6"752 mm16 mm
315/60R1529.9"759 mm15 mm
325/30R2330.7"780 mm23 mm
325/45R1829.5"749 mm18 mm
325/60R1530.4"771 mm15 mm
345/55R1530"761 mm15 mm